Sound head



July 4, 1939.

F. J. LooMls x-r AL 2,164,748

SOUND HEAD Original Filed 001;. 14, 1952 BYH #Ma .f 04.95

l ORN/SY.

l Patented July 4, 1939 UNITED STATES PATENT OFFICE SOUND HEAD aware Original applications October 14, 1932, Serial No. 637,852, and June 26, 1935, Serial No. 28,444.

Divided and Serial No. 142,394

4 Claims.

This invention relates to structure adapted for use in soundheads such as those adapted to be used in combination with motion picture apparatus for the purpose of producing talking motion 5 pictures, and is a division of our applications No. 637,852 filed October 14, 1932, now Patent No. 2,019,147, issued October 29, 1935, and No. 28,444 led June 26, 1935. It will be apparent, however, that its utility is by no means limited to such use.

It has for many years been customary in the talking picture art to provide a sound reproducing mechanism commonly known as a soundhead which is adapted for attachment to a motion picture projector and which is provided with a. drive l5 mechanism common to both the soundhead and the projector so that a single lm carrying both the picture and sound records can be run consecutively through the two instrumentalities and sound can bevreproduced from the film in exact synchronisml with the picture projected from the same lm. The soundhead ordinarily includes an exciter lamp, an ,optical system and a photoelectric cell, although any other desirable form of sound takeoff may be used. The sound record moving mechanism may be mounted inside or exterior to the soundhead. Considerable diilculty has heretofore been encountered in the, past due to the necessity for moving the lm at an absolutely uniform speed past the sound reproduction point, the production of such uniform movement being rendered dicult because of the necessity of moving the lm by means of sprockets cooperating with the sprocket holes therein, and because of irregularities in the operation of the driving mechanism and its attendant gearing.

One object of the invention is the production of a soundhead which is adapted to cooperate with the standard types of motion picture apparatus and which is capable of such an extremely accurate movement of the nlm that a high degree of fidelity of the reproduced sound is realized.

Another object of the invention is the production of such a soundhead having greatest possible simplicity and lowest production cost.

Another object of the invention is the productionA of a soundhead which will permit large manufacturing tolerances and at the' same time produce a device having an extremely high degree of precision.

Another object of theinvention is to provide a roller which will firmly hold the lm in contact with the supporting drum at the reproduction this application May (Cl. T11-2.3)

Another object of the invention is to provide a guide roller which will laterally guide any given standard width of film regardless of the shrinkage thereof.

Another object ofthe invention is to provide 5 a guide roller whose frictional resistance to the film roller is small and whose variations to the resistance are negligible whereby it affects to the least possible extent the motion of the film drum. y 10 Another object of the invention is to provide an f improved pad roller for retaining the lm upon the driving sprockets which is held denitely in position but which is easily adjustable.

Another object of the invention is the provisionl 16 of a pressure roller which will hold the lm upon the lm drum with a uniform pressure and with a minimum of friction.

Another object of the invention is to provide improved pad rollers and means of adjustment 20 therefor for retaining the lm upon the sprockets.

In the drawing:

Figures 1, 2, and 3 show details of the' pressure roller which holds the lm upon the drum. 25

It is necessary, in a device of the class described, that the pressure roller shall hold the lm firmly against the lm drum without slippage; that it rotate so freely as to avoid any interference with the operation of the drum; and 30 that it guide the film laterally to maintain it exactly in position between the optical system and the photocell. This portion of the device is shown in Figs. 1 to 3, inclusive.

The roller surface |00 is formed from a line 35 grade of felt, and after being placed upon the combined spindle and clamping ring |0| is fastened rigidly thereupon by the member |02 and thereafter ground to an accurate circular form. The member |0| is mounted upon a shaft |03 40 which extends entirely through the rotating portions of the unit. This shaft is carried in ballbearings |04 and |05 which are mounted in a bracket hereinafter described and protected by the collar members |06. Mounted firmly upon 45 the shaft and abutting against the collar thereof is the guide member 01 which serves to guide the edge of the film adjacent the soundtrack. The v member |01 is separated from the adjacent ballbearing |04 by the spacer member |08 which, 50 withthe assistance of the nut |09, holds the member |01- firmly against the shoulder on the shaft |03.

The member 0| has fitted rmly thereupon a member ||0 which corresponds in general ap- 5| pearance and function to member |01, but the entire unit comprising the members |00, |02 and ||0 is slidable longitudinally on the shaft |03 and is pressed toward the member |01 by the spring The spring is fixed in position by the collar ||2 which fits against the shoulder on the shaft |03 and is held thereagainst by the nut ||3 and the inner ring of the ball-bearing |05.

` The spacing of the members |01 and ||0 is so chosen that they will be slightly separated when a nlm of the minimum usable width is between them, and will of course be separated a greater distance by wider lm. Due to the long bearing oi' the member |0| upon the shaft |03, the members |01 and ||0 will always remain in exact parallelism, while the entire unit will rotate freely upon the ball-bearings |03 and |05.

The bearings |04 and |05 are supported in the bracket member ||5 which has the ring members H6 and ||1 formed integral therewith. This bracket member is pivoted at ||S in a second bracket member I9. This pivoted joint, as shown in Figs. l and 2, is capable of only a very slight movement and serves to permit a slight vertical movement of the roller |00 in engaging the lm upon the drum 50. The drum |00 is maintained in a firm but yielding engagement with the drum 50 by means of the spring |20 and the ball shown in Fig. l, in which figure they urge the bracket |5 toward the right.

The bracket ||9 is mounted upon the pin |21 which is a press nt in the center plate of the soundhead due to the shaping of the end 22 to fit an appropriately diametered hole in the center plate, in order that the pin |2| may be maintained accurately perpendicular to the said center plate without the in accuracies ordinarily resulting from the tapping of a hole, or the threading of the end of the pin to fit into the tapped hole. The collar |23 fits snugly against the center plate, and against this collar bears the spring |23 ...ich ts, as shown, into a recess in the member i iii and thrusts the member H9 toward the outer end of the pin and against the member |25. The member |25 is threaded upon the outer end oi' the pin i/l so that it may be adjusted longitudinally thereon, is split and provided with a lock-screw |25 as shown. Lateral a-siustment of the side guides |01 and ||il relative to the roller is accomplished by loosening the screw 25 and rotating the member |25 until the guides |01 and are in the proper positions when the member 25 is again locked by 'tightening the screw 26.

It is, of course, necessary to lock the pressure roller in operative position against the roller 50, and to remove it from that position. Locking is accomplished by means of the bolt |21 which is retainer by an appropriate aperture in the center plate, or by an adjustable plate secured thereupon. The bolt |21 is urged toward the center plate by the spring |28 and may be pulled outwardly by the knob |29. A thumb piece is also provided. To open the pressure roller the knob |29 is pulled outwardly, whereby the bolt |21 is removed from its aperture, and the pressure roller is permitted to drop back, while to close it into operating position the assembly is merely rotated by pressure of the member |30 until the bolt |21 snaps into the appropriate aperture, when the entire unit is locked in operating position. In operating position the roller is raised slightly against the pressure oi the spring |20', which then maintains it in contact with the nlm upon the lm drum.

Having now described our invention, we claim:

1. Pressure means for maintaining a film in cooperative relation with an opposing surface comprising a shaft mounted upon anti-friction bearings, a side guide member mounted rigidly upon the said shaft, a sleeve slidable upon the said shaft and carrying a pressure roller and a second side guide, and elastic means urging the said sleeve toward the said fixed side guide.

2. A bracket for supporting a pressure roller comprising a pivoted member, a second member pivoted to said pivoted member for limited movement and biased in one direction, and an arm for supporting the pressure roller extending substantially perpendicularly from said second member in the direction toward which it is biased.

3. A bracket for supporting a pressure roller comprising a pivoted member, a second member pivoted to said pivoted member for limited movement and urged in one direction by a spring, a pressure roller supported upon said second member, and means for manually moving the first of said pivoted members.

4. In combination with film guiding means, a pivot about which the said guiding means is rotatable, an adjustable nut threaded upon the outer end of said pivot, and a spring upon the inner end of said pivot urging said film guiding means toward the said adjustable nut, whereby the position of the said guiding means laterally of the film path can be adjusted.

FRED J. LOOMS. ELLWOOD W. REYNOLDS. 

